Tafsir of As-Saffat 37:100

"Grant me [a child] from among the righteous."

[The meaning is:] "Some of the righteous who will assist me in the call [to God] and in obedience, and who will keep me company in my estrangement." The estimation [of the omitted object] is "a child from among the righteous."

The object was omitted because the verb "grant" (hab) implies it. For in the Quran and the speech of the Arabs, the usage of this verb—when regarding sentient beings—predominantly refers to children.

As for His saying, Exalted is He, {And We granted him his brother Aaron as a prophet}, this is among the exceptions to that predominant usage, or the intended meaning therein is the granting of his prophethood, not the granting of his person, which is a different matter entirely. And this is [further supported] by His saying, Exalted is He...